Pumice Desert

A noteworthy feature north of the lake is the pumice field which is known as the Pumice Desert. The Pumice Desert is a fairly large area, encompassing about 5 1/2 square miles. It is covered by ejecta from the great eruption of Mt. Mazama. A portion of the desert is shown below with Desert Cone visible in the background.

The north entrance road crosses this area between the north entrance gate and the rim of the lake. The road can be seen crossing the desert here with Mt. Thielsen in the background.

The Pumice Desert was formed as a result of the great eruption of Mt. Mazama 7700 years ago. The eruption of Mt. Mazama ejected hot gases, volcanic dust, and glowing, hot avalanches of pumice. Pyroclastic flows (hot, solid, non-liquid particles) from the great eruption buried the basin where the Pumice Desert is now found. Large amounts of pumice and ash were deposited in the area.

Although it was created thousands of years ago, the Pumice Desert is very obviously barren even to the present day. This is quite obvious as it is situated among heavily forested areas. Although some sedges, flowers, grass, and other plants grow on the pumice, the general lack of vegetation is due to the lack of nutrients, the inability of the ground to hold moisture because it is too porous, the climatic extremes to which the area is subjected, and the presence of the western pocket gopher which disturbs seeds before they have a chance to grow.

The eruption of Mt. Mazama covered the valley where the Pumice Desert is now found to a depth of 200 feet. Pumice, which covers the area, is a volcanic rock formed from liquid or pyroclastic ejecta from an eruption. Timber Crater is seen here on the east edge of the desert.

Although the variety of life in the Pumice Desert is not great, there are approximately 14 species of plants which do grow and survive there.